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HelloWorld

Mon Mar 23, 2009 1:54 am


Remove duplicate values from an array?

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I just started learning PHP, and I've been having lots of fun. I made a little tool for myself that works great, but I want to improve it. My tool does a search, and returns results in an array. Sometimes there can be duplicates in the results, how can I remove those from the array?

Here is what I mean:

Array
)
   [0] => blue
   [1] => red
   [2] => orange
   [3] => green
   [4] => orange
   [5] => red
   [6] => yellow
)

I want to remove the repeats. So in the end it will be:

Array
)
   [0] => blue
   [1] => red
   [2] => orange
   [3] => green
   [4] => yellow
)

Thanks :).


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btiffin

Mon Mar 23, 2009 11:22 am


RE:Remove duplicate values from an array?

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Look at array_unique

Cheers


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A.J

Mon Mar 23, 2009 11:30 am


RE:Remove duplicate values from an array?

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array_unique or try hashing the values. maybe store the colors as numbers.


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HelloWorld

Mon Mar 23, 2009 2:40 pm


RE:Remove duplicate values from an array?

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Great. Thanks for the help. :)


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DanielG

Sat Mar 28, 2009 7:52 pm


RE:Remove duplicate values from an array?

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if your arrays are tiny, you can always just compare EVERY value with EVERY value before it to see if there is a repeat.


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Analysis Mode

Sat Mar 28, 2009 8:26 pm


Re: Remove duplicate values from an array?

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Why don't you sort them?  That way, you can delete duplicates in O(N) time and not O(N^2) time.


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DemonWasp

Sat Mar 28, 2009 8:36 pm


RE:Remove duplicate values from an array?

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...or you could insert all the values into some sort of Set object (preferably the PHP equivalent of a HashSet), which would do it all in O ( N ) time - whereas sorting first requires O ( N * log ( N ) ) time.